DTBBA was nominated in 2007 by the National Cancer Institute for National Toxicology Program (NTP) toxicology and carcinogenesis studies. The nomination was based on high and increasing production volume, the potential for occupational and consumer exposures, the lack of adequate toxicology and carcinogenicity data, and suspicion of toxicity based on the structure of the chemical. There is limited environmental and occupational exposure data available in the scientific literature to assess the scope of DTBBA industrial exposure and there is no current analytical method to quantitatively assess DTBBA airborne particulate and surface exposures. The study will involve exposure surveys among facilities representing manufacturers and/ or industrial users of DTBBA compounds. An analytical method for DTBBA has been completed. The manufacturing/ industrial usage profile of DTBBA to characterize industry wide occupational exposures including total number of workers and evaluate patterns of exposure to DTBBA has been completed. An industrial hygiene sampling survey (that collected air and wipe samples) has been completed at 1 DTBBA user and 1 additional sampling survey is planned at a second user with completion expected by the end of FY10. Once the data collection has been completed, the industrial hygiene survey report that details range of exposures and suggested countermeasures for the above sites will be prepared.